package org.qing.service;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.support.AbstractApplicationContext;

public class SpringContextUtil implements ApplicationContextAware {
	private static ApplicationContext applicationContext; //Spring应用上下文环境

	/**
	* 实现ApplicationContextAware接口的回调方法，设置上下文环境
	* @param applicationContext
	* @throws BeansException
	*/
	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
		SpringContextUtil.applicationContext = applicationContext;
	}

	/**
	* @return ApplicationContext
	*/
	public static ApplicationContext getApplicationContext() {
		return applicationContext;
	}

	/**
	* 获取对象
	* @param name
	* @return Object 一个以所给名字注册的bean的实例
	* @throws BeansException
	*/
	public static Object getBean(String name) throws BeansException {
		((AbstractApplicationContext)applicationContext).refresh();
		return applicationContext.getBean(name);
	}

	/**
	* 获取类型为requiredType的对象
	* 如果bean不能被类型转换，相应的异常将会被抛出（BeanNotOfRequiredTypeException）
	* @param name bean注册名
	* @param requiredType 返回对象类型
	* @return Object 返回requiredType类型对象
	* @throws BeansException
	*/
	public static Object getBean(String name, Class requiredType) throws BeansException {
		return applicationContext.getBean(name, requiredType);
	}

	/**
	* 如果BeanFactory包含一个与所给名称匹配的bean定义，则返回true
	* @param name
	* @return boolean
	*/
	public static boolean containsBean(String name) {
		return applicationContext.containsBean(name);
	}

	/**
	* 判断以给定名字注册的bean定义是一个singleton还是一个prototype。
	* 如果与给定名字相应的bean定义没有被找到，将会抛出一个异常（NoSuchBeanDefinitionException）
	* @param name
	* @return boolean
	* @throws NoSuchBeanDefinitionException
	*/
	public static boolean isSingleton(String name) throws NoSuchBeanDefinitionException {
		return applicationContext.isSingleton(name);
	}

	/**
	* @param name
	* @return Class 注册对象的类型
	* @throws NoSuchBeanDefinitionException
	*/
	public static Class getType(String name) throws NoSuchBeanDefinitionException {
		return applicationContext.getType(name);
	}

	/**
	* 如果给定的bean名字在bean定义中有别名，则返回这些别名
	* @param name
	* @return
	* @throws NoSuchBeanDefinitionException
	*/
	public static String[] getAliases(String name) throws NoSuchBeanDefinitionException {
		return applicationContext.getAliases(name);
	}
} 